(a). Field of the Invention
The present invention relates to a dual mode shift lever unit for an automatic transmission, and in particular, to a detent mechanism for a dual mode shift lever unit having automatic and manual modes capable of enhancing detent quality while in mode conversion.
(b). Description of the Related Art
Recently, high class automobiles have tended to be equipped with a dual mode transmission shift mechanism for satisfying driver""s whimsical tastes to sometimes take the pleasure of manually shifting the transmission like a sports car, and sometimes to enjoy ride quality of an automatic operation of a high class sedan.
This kind of dual mode shift mechanism provides two shift modes, i.e., an automatic mode and a manual mode, such that an indicator panel is formed having a guide groove separating respective mode portions.
FIG. 1 is a top plane view showing a presently used indicator panel. FIG. 2 and FIG. 3 are respective side elevation and internal perspective views of a dual mode shift lever unit which is presently used, and FIG. 4 is a perspective view of a shift lever of the dual mode shift lever unit as presently used.
As shown in FIG. 2, the dual mode shift lever unit comprises a shift lever 2 inserted into a housing 1 through a guide groove formed on an indicator panel at an upper part of the housing 1, and a cable bracket 3 which is pivotally supported by the housing 1 and connected to a transmission manual valve (not shown) by a cable (not shown) such that the transmission manual valve is responsively operated by shift lever manipulation.
In terms of mode conversion, the shift lever 2 moves in widthwise directions in relation to the vehicle""s direction of travel at a D range. Normally, the shift lever 2 is located in automatic mode in which the shift lever is connected to the cable bracket 3 by engaging a pin 4 formed on the shift lever 2 with a pinhole 5 formed on the cable bracket 3 such that the shift lever can move to and fro along an automatic mode groove by driver""s manipulation.
To convert the mode to the manual mode, the shift lever 2 moves in an opposite side direction at the range D in order for the pin of the shift lever to be disengaged from the pinhole of the cable bracket 3.
FIG. 3 shows that under the indicator panel a guide rail 6 is fixedly mounted along the automatic mode portion and has a guide groove 7 such that a guide projection 9 having an L-shape, downwardly bent on one side of the shift lever 2, is guided along the guide groove 7 of the guide rail 6 during range shifting in automatic mode.
Also, the shift lever 2 is provided with a detent mechanism (see FIG. 4) at it lower end portion so as to provide detent quality when changing the mode from automatic mode to the manual mode or vice versa.
As shown in FIG. 4, the detent mechanism comprises a bracket 240 having a pair of parallel arms 251 formed in a middle portion thereof and fixedly mounted to the lower end of the shift lever 2 at its upper end and pivotally connected to a rotation member 250, which also pivots on a pivot shaft 245 such that the shift lever can pivot in front, rear, left, and right directions; and a detent block 253 pivotally connected to the bracket 240 at it""s lower portions by a pin 254 crossing between two opposite walls of the bracket 240 and biased to a bar 252 installed between the parallel arms 251 of the bracket 240 by a coil spring 256 which is supported by a support 260 integrally formed with the rotation member 250 such that the detent block 253 is hooked to the bar 252 at one of two recesses 255 formed on the detent block vertically arranged with respect to the pivot shaft 245.
Practically, while the shift mode is converted from the automatic mode to the manual mode, i.e., the bracket 240 pivots to push the detent block 253, the detent block 253 moves to overcome a biasing force of the coil spring 256 such that the bar 252 slides down to engage with a lower recess.
However, this dual mode shift lever unit has drawbacks in that the coil spring for elastically biasing the detent block is unstable so as to be easily deviated from its place resulting in degraded detent quality.
The present invention has been made in an effort to solve the above problems of the prior art.
It is an object of the present invention to provide a dual mode shift lever unit capable of providing a reliable detent quality during a mode conversion operation, and to provide durability by simplifying the structure of a detent mechanism.
To achieve the above object, the detent mechanism for a dual mode shift lever unit comprises a bracket fixedly connected to a lower end of the shift lever and pivotally connected to a rotational member which is rotationally mounted on a pivot shaft supported by a shift lever housing, a support member integrally formed on one end portion of the rotational member and extended in an upward direction, and a turnover spring installed onto one open side of the bracket for contacting the support member.